The influence of transpiration rate on the uptake and translocation of two industrial waste compounds, phenol and nitrobenzene, and one pesticide, 5-bromo-3-sec-butyl-6-methyluracil (bromacil), was examined. Carbon-14 moieties of each compound were provided separately in hydroponic solution to mature soybean plants maintained under three humidity conditions. Bromacil was taken up slower than the other chemicals, had the most 14C translocated to the shoot, and the amount translocated to the shoot responded directly to the rate of transpiration. In contrast, both phenol and nitrobenzene were rapidly lost from solution and bound to the roots. Less than 1.5% of the 14C from phenol or nitrobenzene was translocated to the plant shoots. Increased transpiration rates had little influence on root binding of 14C; however, increasing transpiration rate from low to medium was associated with an increased uptake of nitrobenzene.